famousky

你们好 麻烦个问题:
我把<div class="Pcontent">
<script language="javascript" type="text/javascript">
<!--
//document.write("");
function show_date_time(){
window.setTimeout("show_date_time()", 1000);
BirthDay=new Date("03-25-2006");//改成你的计时日期
today=new Date();
timeold=(BirthDay.getTime()-today.getTime());
sectimeold=timeold/1000
secondsold=Math.floor(sectimeold);
msPerDay=24*60*60*1000
e_daysold=timeold/msPerDay
daysold=Math.floor(e_daysold);
e_hrsold=(e_daysold-daysold)*24;
hrsold=Math.floor(e_hrsold);
e_minsold=(e_hrsold-hrsold)*60;
minsold=Math.floor((e_hrsold-hrsold)*60);
seconds=Math.floor((e_minsold-minsold)*60);
span_dt_dt.innerHTML=daysold+"天"+hrsold+"小时"+minsold+"分"+seconds+"秒" ;
}
show_date_time();
//-->
</script>
<div ><span style="COLOR: #990000">距离<span style="FONT-WEIGHT: bold">考研复试</span>还有</span>
            <span id="span_dt_dt" style="BORDER-TOP-WIDTH: 0px; BORDER-LEFT-WIDTH: 0px; BORDER-BOTTOM-WIDTH: 0px; BORDER-RIGHT-WIDTH: 0px">￡</span>

插入网页  告诉我:span_dt_dt未定义!

这个错误是怎么回事,怎么改呢??